By Anna-Marie Lever
Science and Nature reporter, BBC News
Returning home. Dink and James swim off into the ocean
Two loggerhead turtles, which were washed up on the south-west UK coast this winter, have been flown to Gran Canaria and released back into the sea.
Twenty-three loggerheads have been stranded on UK and Irish coasts this year, an unprecedented number. "Dink" and "James" were the only survivors.
Having tenderly nursed the turtles back to health, Blue Reef Aquarium curator Matt Slater said he was "delighted".
Loggerheads (Caretta caretta) are categorised as endangered.
"Hopefully, we won't be seeing you again. Have many, many years of swimming in the ocean," Mr Slater called out to Dink and James as they disappeared into the clear water.
After six months of rehabilitation at Blue Reef Aquarium, Newquay, the two loggerheads have been returned to the sea off a beach in Las Palmas, Gran Canaria.
"It was absolutely beautiful. Let's hope no more turtles get stranded, but if they do we know we can look after them," Mr Slater said.
Both turtles have been microchipped. If they are ever spotted again, by fishermen or on the beach, a tag in their flipper can be used for identification. Otherwise, their adventures in the vast Atlantic Ocean will be unknown.
"I hope they will be OK," Mr Slater mused. "In their lifetime, things will change a lot. The future for turtles in general is not great."
After arriving in Gran Canaria, Dink and James were checked over and given the all-clear at the Wildlife Recovery Centre of Tafira. Some 150 injured turtles from around the Canary Islands are taken here each year.
"Seventy-five percent of the sea turtles that we receive have been hurt because of man's activities," said Pascual Calabuig, the centre's director.
He added: "We see turtles damaged by hooks, nets, pollution, oil and plastic bags. Turtles damaged by boats are the worst to recover. We try to patch up their shells with fibreglass, but survival rates are low.
"Through diagnosis, treatment, operations, protein-rich food, fluid and antibiotics, we help save 80% of the turtles that we receive," said Mr Calabuig.
Along with industrial fisheries, habitat loss and climate change are the main threats facing turtles.
It was Mr Calabuig's excellent reputation and his centre's track record that helped Blue Reef decide to choose Gran Canaria as the release site.
"We could also get cheap flights and the Canary Islands are the nearest land point to the loggerheads' migration route around the Atlantic," explained Mr Slater.
Drifting on the current
Loggerheads breed on the beaches of the Mediterranean, West Africa, Brazil and along the south-east coasts of the US. Florida has the largest loggerhead population.
"Within 24 hours hatchlings swim into the open water of the Atlantic Ocean," explained Peter Richardson, biodiversity programme manager at the Marine Conservation Society.
Loggerheads travel around the large ocean currents in a wide loop. From nesting beaches in Florida, they follow the Gulf Stream across the Atlantic to Madeira, and then head south to the Canary Islands and Cape Verde Isles, before heading back to the south-east coast of the US.
Mr Richardson added: "They join the North Atlantic Gyre's circulatory system for three to five years before coming inshore. They then gradually move towards a nesting beach in the vicinity of where they were born."
He continued: "We are not 100% sure how turtles navigate this route. They have some geo-magnetic understanding, for broad-scale navigation, and can use chemical cues coming off of islands, such as windblown dust, as a homing device."
Why UK strandings?
Scientists are uncertain why loggerhead turtles have been stranding on UK and Ireland coasts in record numbers this year.
Most agree that extreme weather systems over the UK may be a cause.
"From December to February we had strong and persistent south-westerly winds towards UK shores. Small or compromised turtles in the north-east Atlantic may have drifted off-course because of this," explained Mr Richardson.
Loggerhead turtles are hard-shelled and unable to raise their body temperature in order to survive in the cold UK waters.
Mr Richardson adds: "At 15C (59F) the turtles stop feeding and at 10C (50F) they shut down."
Unable to feed, the loggerheads became lethargic and drifted inland.
Mr Richardson also suggests a rare unseasonable jellyfish bloom at the end of November off the west coast of the UK may also have contributed to an increase in strandings.
"Juvenile loggerheads are opportunistic feeders. The jellyfish may have attracted them off their normal course. Then they may have got caught in a weather system and blown over."
Mr Brendan Godley, a conservation biologist at the University of Exeter, suggests another possibility: "It may simply be because there are more hatchlings in the open water.
"The Florida population of loggerheads has increased since the 70s because of good conservation. The more hatchlings there are out there, the more likely that some may be stranded."
Rescue and recovery
Curator Matt Slater followed Dink and James on their journey back to the wild.
James was stranded on Blackrock Beach, Bude, on 26 January this year, and Dink a week later further up the coast at Putsborough Beach, Woolacombe.
"They were both in a poor state when they arrived," explained Mr Slater. "James was particularly bad. It was touch and go for a while.
"Being a larger, more powerful turtle, James is thought to have battled the strong currents, which left him exhausted. Dink, being younger, probably endured less stress as he just drifted on the current and arrived inland faster."
James was suffering from pneumonia, dehydration and a lung infection when he arrived. Both turtles had hypothermia.
James had to be tube fed when he first arrived at Blue Reef
Dink and James were warmed up steadily but slowly. The water temperature of their rehabilitation tanks was increased from 10C, the temperature of the UK sea in January, to 25C.
"As a result, their metabolism speeded up and they are able to heal faster," said Mr Slater.
"James was put on a course of antibiotics and anti-fungals to cure infection. When he first took food by himself, after two weeks of tube feeding, we knew he was on the road to recovery."
After six months of dedicated rehabilitation, the turtles had reached peak condition and were ready for repatriation.
They flew to Las Palmas, Gran Canaria, on Monday 23 June and were released on a beach two days later.
While the Cetacean Stranding Investigation Programme (CSIP) is funded to investigate cause of death in marine animals that strand around the UK, no such funding is available for animals that strand alive. James and Dink were given their second chance back in the ocean through generosity and goodwill.
Have you seen any loggerhead turtles? Do you have any pictures of the turtles?
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.